Cracked Mirror
by Dark Ice Dragon
Summary: M-21 finds himself in a familiar place he doesn't want to be and meets a familiar face that shouldn't be there. From there it goes downhill.
1. Chapter 1

**Summary** : M-21 finds himself in a familiar place he doesn't want to be and meets a familiar face that shouldn't be there. From there it goes downhill.

I finished writing a third part sooo I'll just move this to it's own post too.

* * *

 **Cracked Mirror  
**

By Dark Ice Dragon

* * *

M-21 frowned as he walked down the pristine corridors that screamed Union lab at him. He'd been in them enough times to recognise the fucking fake _plant_ all their labs had, bulk-buying them from the same place, probably.

This had to be a dream. Why else had he found himself in a lab without remembering how?

Except...

M-21 pursed his lips. There was far too big a chance he'd been kidnapped and his memories erased.

Dread grabbed him but M-21 shoved it down, still moving forward. He could worry when he found something. And to do that, he needed to get out. He avoided approaching footsteps, but he didn't have to do that often. There weren't any windows or clocks on the walls, but it had to be night.

A double-door to M-21's left slid open and-

Huh.

He had to be dreaming then — it was Frankenstein that stepped out from the room, wearing his usual labcoat.

M-21 relaxed, a smile starting to curl his lips. All he had to do was wake up then.

A frown tugged Frankenstein's down lips, his eyebrows drawing in as he looked M-21 up and down. Assessing him. M-21's smile faded, the hairs at the back of his neck raising.

"M-21, where did you get that suit?" The question was mild, softly asked, but M-21 recognised his sharp look.

Unease grew in M-21. Or his dream was diving into a nightmare, because Frankenstein was looking at him like a Union scientist: M-21 was just a convenient source of data for him, nothing of worth.

"I bought it."

"Oh?" Frankenstein raised his eyebrows as he tilted his head. "With what money…?"

M-21 gritted his teeth, wanting this nightmare to _end_ already, especially with the implications it was giving him. "With the money _you_ paid me, Frankenstein."

Frankenstein smiled. It didn't reach his eyes, his gaze calculating, like M-21 had upgraded himself into something that piqued his interest. Something that needed to be studied _right now_. "And where did you hear that name, mm?" Frankenstein purred, advancing on him. The movement made something swing on his breast pocket: there was an ID card clipped there, the name on it simply stating 'Dr. Lee'.

This was wrong. Not just how Frankenstein was acting, but everything felt too _real_. M-21's instincts were screaming at him to run, his heart kicking up in preparation, ready for him to transform. And he'd been so distracted with Frankenstein he hadn't noticed there were people approaching from behind.

M-21 backed up a step, swivelling around to see who was behind him and froze.

There were three people walking up, two of them in labcoats flanking the third. It was the third person that made M-21 stop, his brain trying to understand what was in front of him.

The person in the middle was _himself_ , wearing the all too familiar plain clothes of experimental material.

He wasn't an exact copy: his hair was longer than M-21's had been, falling past his shoulders, his skin so pale it must have been years since it had been touched by the sun. Those differences weren't what made M-21's stomach twist at the sight of him.

It was the old scars that circled his double's neck and wrists, sunk in enough that chunks of flesh must have been torn out. M-21 could see the line of restraints, but there were others that spread out like they'd traced up veins to reach further and damage more.

And what made M-21's temper flare was he _recognised_ those injures, the purple so dark it was almost black imbedded in the skin. He'd had them once before and M-21 snarled as he transformed, whirling around and slashing at the fucking _bastard_ that had Frankenstein's face.

A black shield threaded with purple snapped up in time to protect Frankenstein, not that M-21 expected anything less. As Dark Spear shot out at him, M-21 arced his arms up, tearing through the ceiling.

He hadn't passed any windows and everything pointed to them being in an underground lab. M-21 was rewarded with the ceiling caving in with a fountain of dirt and debris pouring in through the holes he'd created to block the corridor.

It wouldn't stop Frankenstein for long, M-21 already feeling the warning prickle of Dark Spear gaining in strength. The scientists had scrambled back at the fight, one of them fallen back on their ass, and the sound of their blood splattering against was the wall was _so fucking satisfying_ , their cooling blood on his fingertips feeling real as they dripped from his claws.

"Come on!" he snapped as his wide-eyed double, lunging forward and grabbing him above where Dark Spear had bit, pulling him down the corridor.

Wherever M-21 was, whatever was happening, he wasn't going to let someone like him be used as experimental material if he could help it.

* * *

Inspired by sharingwritingprompts' 'An accident throws a person into the wrong timeline, and the only one who understands what happens is the person who was their mortal enemy in their proper timeline.'


	2. Chapter 2

**Summary** : : Staircase conversation.

Contains mentions of Union!Frankenstein being a Union scientist, and the mistreatment of experiments. Abusive relationship undertones.

Using up all the italicises I hadn't for the other fics, pfft.

Thanks to Hellse Bunny for listening to me and helping me while I wrote this. 83

* * *

 **Cracked Mirror  
**

By Dark Ice Dragon

* * *

M-21 stumbled up the stairs, still not sure if he was following someone who looked so much like him apart from missing a few scars or a hallucination. The hand clasped around his arm felt real, a steady pressure that wasn't tight enough to hurt.

"Where - where are we going?" He almost couldn't keep up with his twin, and there had been a few times where a quick yank to his feet had saved him from tumbling over.

"Where do you think?" his twin said, still climbing the emergency staircase. "The fuck out of here."

M-21 stopped, trying to rip his hand out of his twin's grip. His twin's hand didn't let go, but he did stop to frown at him.

"What?" his twin said.

" _Outside_?" M-21 gaped, taking a step back, this time his twin letting go. He couldn't. Everything that had happened crashed around him, and Doctor Lee was going to be _so mad_. Two scientists were dead, a _mess had been made_ , and he'd run from the punishment-!

He had to go back. The faster he did, the less mad Doctor Lee would be.

...Doctor Lee would still be mad, but the punishment wouldn't be as long if he grovelled and promised to never do it again.

"Yeah, outside." His twin eyed him, his lips pursed. "You want to stay _here_?"

M-21 stared at him. "How do you not - there are _mutants_ outside!"

 _That_ seemed to startle his twin, his eyes going wide. "Mutants?" Then he shook his head, snorting. "How do you know they weren't just saying that to keep you in line?"

"I..." M-21 kept staring at his twin. "I've seen them," he said. Their twisted bodies that got dragged in for Doctor Lee to study. Seeing one meant M-21 and his comrades wouldn't be experimented on while Doctor Lee was distracted with a new body different from the last one. They were becoming less recognisable as human, backs hunched over to let them run on all fours, slobbering jaws filled with sharp fangs, their skin a discoloured grey.

Understanding softened his twin's face. "And it's better to be here than outside."

M-21 nodded. He was experimental material here, but he was _alive_ rather than a mutant or the mangled mess they left behind.

"So you've never thought about a time where you weren't just waiting to be experimented on?"

M-21 let out a choked laugh. "You think I could survive out there?" He waved a hand towards the ceiling.

"Yeah." His twin's gaze was steady and confident. "You're stronger than you think." M-21 was about to scoff but his twin continued. "You've survived all the time - and why do you think you have to be restrained so tightly?"

M-21 paused at the question. He was the only one of his comrades who Doctor Lee still used Dark Spear with. It had been because he'd been so unwilling to bend at the start, but... "Only because Doctor Lee knows the limit of human bodies..." But...it sounded hollow. Reaching. What if...?

There was a terrifying feeling of hope building in M-21's chest. It had to be crushed before it overwhelmed him, because hoping had led to nothing before and it hurt so much to fail.

...Could he actually live and not pay for that privilege with his body being experimented on?

His mouth moved before he could stop it, still powered by that damnable hope. "Do you think my comrades would become as strong as me?" Why was he different from them? How could he transform when they-

" _What_?" His twin's eyes were wide again. "Your - how many?" he demanded.

"All?" What did he mean? "There's a hundred of us."

For the first time, M-21 saw his twin pale, using the banister to hold himself upright as he trembled.

M-21 watched him collect himself, but why had _that_ piece of information been so shocking for him...?

* * *

So I realised that if Frankenstein decided to get into human experimentation because of self-interest rather than protecting humanity, there wouldn't have been someone to call out nobles about their involvement with mutants... Honestly, after 800 years there really shouldn't have been much of humanity left but yeah.


	3. Chapter 3

**Summary** : Doctor Lee speaks with the M-21s.

Contains brief mention of torture. Union!Frankenstein being a Union scientist, and the mistreatment of experiments.

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 **Cracked Mirror  
**

By Dark Ice Dragon

* * *

M-21 still wasn't sure what to make of his twin's reaction when the PA system hissed, making him snap his attention to it.

[I would hate to interrupt such an interesting conversation,] Doctor Lee's voice announced, [but-]

"Fuck _you_ , bastard!" M-21's twin snarled and M-21 froze, the air trapped in his lungs as his throat closed up, ice flooding his body.

No nonono, what was he _doing_? Maybe if he- "Doct-!"

A scream pierced through the air and M-21 flinched, recognising M-38's voice. His fault. This was _his fault_. If he hadn't ran - M-21 struggled to breathe, M-38's scream echoing in his mind as blood roared in his ears.

[My my,] Doctor Lee said, his tone amused, and M-21 wanted to be sick, still hearing M-38's muffled whimpering, [it looks as if you haven't been trained yet, so I will allow for one warning.]

This time his twin thankfully didn't say anything, though both his hands were clenched into fists as he glared at the speakers.

[That's better. Now then, I want you both at the M-series quarters as soon as you can. The longer you make me wait and if either of you transform, well, I'll be feeding Dark Spear some of your comrades' limbs, understand?]

M-21 swallowed and nodded. "Yes, Doctor Lee."

There was a pause and M-21's mind raced, trying to figure out what he'd done wrong.

[I do expect an answer, M-21.]

But he _had_ -!

The soft growl coming from his twin made the hair at the back of M-21's neck raise, and his twin _still wasn't saying anything_. Another second dragged out, a muscle twitching in his twin's jaw, and M-21 strained his ears, expecting another comrade's scream for the disobedience.

"Yes, sir." The words were forced out through gritted teeth and M-21 could see his fangs poking out from under his lips.

[Ah, so you _were_ trained at one point. How lax of your scientist to not reinforce good behaviour.]

His twin's growl was ratcheting up with each word and M-21 caught his eye, shaking his head with as little movement as possible. Doctor Lee was being _so tolerant_ of his twin's insolence right then, but Doctor Lee's patience only lasted so long.

The growl cut off with a hiss, his twin's expression blanking though the clenched muscle was still there.

[Never mind; I'll make sure to train you well once you're here. Though I prefer Doctor Lee over sir.]

M-21 only had to wait one second before his twin said, "Yes, Doctor Lee."

[Well done! You're a fast learner. Now then, I expect to see both of you soon.]

The speakers fell silent and M-21 sagged against a wall, his legs wanting to collapse under him. He turned to his twin, who was breathing harshly, blood dripping from his shaking fists.

"Please..." M-21 whispered, watching him with a knotted stomach. His twin could still try to leave and he didn't have the strength to drag him back. If both of them didn't return, everyone would be punished. Everyone could _still_ be punished and it was _his fault_.

His twin gave him tight nod, unfurling his hands. "Let's go."

Relief washed over M-21 and he turned and bolted in the direction of his quarters, hearing his twin follow.

* * *

I was going to write something else from canon!M-21's pov, but then I decided to not have Doctor Lee as the Crombell villain who sits back and observes everything.


	4. Chapter 4

**Summary** : M-21 meets Doctor Lee again.

Contains torture. Union!Frankenstein being a Union scientist.

* * *

 **Cracked Mirror  
**

By Dark Ice Dragon

* * *

M-21's double was panting by the time they reached a innocuous door that had a small plate next to it saying, 'M-series'. They hadn't run _that_ far but if his double had never left this lab or been trained as an agent...

A sense of foreboding grew in M-21 as they reached the door, his skin prickling again. There were two armed guards on each side of the door, who watched them approach but didn't do anything else. M-21 already knew what was on the other side, and he gritted his teeth again, seeing his double swipe his wrist over a scanner by the door.

The door slid open and they stepped inside.

The room was filled with people, all of them wearing the same clothes of an experimental material. There were so many around him, M-21 could only see one or two faces he recognised, his stomach churning. This was how many the Union had sacrificed for power, this was how many people he'd never even had the chance to _meet_ before the Union had killed them.

The air was heavy as they entered, and it wasn't because the room was silent, all eyes on them.

Dark Spear loomed overhead, a multitude of spears hanging above them, each pointing to a different comrade.

M-21 was used to Frankenstein calling on Dark Spear when he was annoyed at a mess (or annoyed in general), but he had only used it as a warning, keeping enough control that the threat was a distant one and not directed at someone under his care.

The Dark Spear here was on the edge of striking out, on feasting on whatever was closest to it, straining against its leash.

 _Doctor Lee_ was in the centre of the room, his hands in his pockets, and while there wasn't a visible bloodstain on the tiles, M-21 could smell the freshly spilled blood. There was a small huddle of people to M-21's right and that had to be where the hurt comrade was.

He trapped the growl in his throat, keeping his hands loose by his sides. He couldn't piss off Lee like he would with anyone else in this situation, not when Lee would hurt the others in retaliation.

Lee's assessing gaze on him made M-21's skin itch, watching how M-21 moved rather than seeing _him_.

Lee smiled when they stopped in front of him, M-21's double trying to keep his sharp breathing under control. They were _so close_ to Lee it would just be one swipe to take the bastard's head off, but M-21 didn't know how fast Lee's reactions were, and all of the M-series could die at a thought. And he didn't know what Dark Spear would do either, if it would fade away when Lee died or if it would be unleashed on all of them without Lee controlling it.

"I was starting to wonder if you were ever going to arrive," Lee said and M-21 held back his sneer.

 _Liar_. Lee had known where they were so he would have _known_ they were coming.

"Sorry, Doctor Lee," his double stuttered, ducking his head as he trembled.

M-21 said the same, lowering his gaze. He'd had to do that for Crombell, but this time, loathing boiled his gut rather than the icy chill of the possibility of being found useless by the Union or his and M-24's abilities discovered.

"I see you haven't forgotten _all_ of your training, M-21, and hm, I suppose I'll need to make you a new name to differentiate you from my M-21."

M-21 gritted his teeth. _His_ M-21? No-one was _his_. "Thank you, Doctor Lee." Because he was supposed to be _thankful_ a scientist wanted to give him a name.

Lee's lips curled up into a smile before saying, "Now then, where were we?" M-21's double sucked in a breath, and M-21 glanced at him from the corner of his eyes. "Ah yes-"

A spear flashed down and his double screamed, collapsing. M-21's nostrils flared at the blood splattered across the ground, Dark Spear wrapped around his double's legs.

"- _punishment._ " The word was said with relish, like the fucker _enjoyed_ hearing the screams but he was a Union scientist so obviously he did.

"Stop it!" M-21 roared, his nails already lengthening. "He shouldn't be - I'm the one who dragged him away!"

His double's screams didn't stop.

"He could have tried to get away from you at any time. He didn't," Lee said, watching his double writhe. "He needs to _remember his place_. This way, he'll think twice before trying to run."

Because of the punishment and Lee had left his legs a wreck as Dark Spear faded from sight. Even if his double had as good healing as he did, Dark Spear still interfered with a modified human's regeneration ability.

M-21 wanted to check how his double was doing (not that he would be able to help, but at least his double would know he was _there_ ) but if he moved without Lee's _permission_ he was sure someone else would be hurt again.

"Eye contact," Lee said, looking at him.

What? Yeah he was - M-21 forced his gaze down, wiping the glare off his face.

His double's screams had petered off, replaced with panting.

"And as for you..." Lee's hands were moving like they were caressing an invisible ball. In the centre, Dark Spear was forming, growing bigger. It was in its spear shape for a second before it looped on itself, creating a circle. It was still growing, the band...flattening.

 _Bastard_.

Once Lee was done, Dark Spear looked like black metal, the band barely wider than M-21's pinkie. The size of it was too big for M-21's wrists.

It was the perfect size to go around M-21's throat.

Lee presented M-21 with the collar, one part sliding open without a clasp. M-21 stared at it for a second and then took it from him before Lee decided he'd hesitated for too long.

His skin prickled where he touched the collar, Dark Spear already trying to latch onto him.

It was a trap. He knew that. He was binding himself, giving himself less chance of escape. But he couldn't risk the chance the others being hurt if he refused.

M-21 placed the collar against his throat, making sure the two edges touched. It rested against his Adam's apple, tight enough to be aware of its presence there but loose enough it didn't restrict his breathing. Dark Spear was warm against his throat, not cold, and it thrummed against his skin.

"Urk!"

Dark Spear tightened, tendrils digging into his skin. It coursed through his veins, leaving fire in its wake like it was trying to hollow him out.

His heart picked up speed in response, M-21's regeneration kicking in.

Dark Spear crawled up his neck and M-21 hissed, his throat working to growl, but Dark Spear was forcing his transformation back.

His heart wasn't calming down, thudding so hard it seemed it would give out first before it slowed again.

The seconds dragged as M-21 panted, his heartbeat roaring in his ears and then Dark Spear retreated, drawing back into the collar. M-21's heart slowed again, leaving him chilled. Sweat beaded over his skin as M-21 swallowed, the collar pressing against his neck.

The room was brighter. Not just because of the light at the corners of his vision, but because Dark Spear was gone from the ceiling.

"Now that we've made sure there won't be any surprises," Lee said, "it's time for your check up."

M-21 sucked in a breath. "Yes, Doctor Lee," he said, making sure his voice didn't crack or waver.

Lee smiled at that, like he'd found an interesting challenge in front of him, but like _fuck_ he was going to let that bastard break him. 

* * *

Was going have Doctor Lee made manacles as well but thought that might have been a little bit of overkill, haha.

The next part should be a breather episode, but I should be concentrating on Nano, haha.


End file.
